// Copyright (C) 2021 nytpu
// SPDX-License-Identifier: AGPL-3.0-or-later
// For more license details, see LICENSE or <https://www.gnu.org/licenses/agpl-3.0.html>.

package fetch

import (
	"bytes"
	"crypto/sha256"
	"fmt"
	"io"
	"time"

	"github.com/mmcdole/gofeed"
	"github.com/prologic/go-gopher"

	"golang.nytpu.com/comitium/core"
)

// fetchGopher will make a request for a gopher resource
func fetchGopher(remote string) (*gopher.Response, error) {
	resp, err := gopher.Get(remote)
	if err != nil {
		return nil, err
	}
	return resp, nil
}

// gopherFeed will fetch and insert a new core.Feed into a core.FullData given a
// gopher url (or update if it's preexisting)
func gopherFeed(data *core.FullData, remote string, title string) error {
	resp, err := fetchGopher(remote)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	if len(resp.Dir.Items) != 0 {
		// TODO
		return fmt.Errorf("Gemini-style feeds served over gopher are currently unsupported.")
	}

	reader := io.LimitReader(resp.Body, 1073741824) // 1 GiB
	gofeed, err := gofeed.NewParser().Parse(reader)
	if err != nil {
		return err
	}
	feed, err := core.GofeedConvert(gofeed, title)
	if err != nil {
		return err
	}
	data.InsertFeed(feed, remote)
	return nil
}

// gopherPage will fetch and insert a new core.Page into a core.FullData given a
// gopher url (or update if it's preexisting)
func gopherPage(data *core.FullData, remote string, title string) error {
	resp, err := fetchGopher(remote)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	var reader io.Reader
	if len(resp.Dir.Items) > 0 {
		text, err := resp.Dir.ToText()
		if err != nil {
			return err
		}
		reader = io.LimitReader(bytes.NewReader(text), 1073741824) // 1 GiB
	} else {
		reader = io.LimitReader(resp.Body, 1073741824) // 1 GiB
	}

	var page core.Page
	page.Title = title
	page.Link = remote
	h := sha256.New()
	if _, err := io.Copy(h, reader); err != nil {
		return err
	}
	newHash := fmt.Sprintf("%x", h.Sum(nil))
	page.Hash = newHash
	page.Updated = time.Now()

	data.InsertPage(&page, remote)
	return nil
}